In automation technology, especially in process automation technology, field devices are often applied, which serve for registering and/or influencing process variables. Examples for such field devices are fill level, measuring devices, mass flow measuring devices, analytical measuring devices, pressure and temperature measuring devices, etc., which, as sensors, register the corresponding process variables, fill level, flow, pressure, pressure difference, pH-value, or temperature.
Serving for influencing process variables are actuators, e.g. valves or pumps, via which the flow of a liquid in a pipeline section, or the fill level in a container, can be altered.
A large number of such field devices are available from the members of the firm, Endress+Hauser.
As a rule, field devices in plants equipped with modern automation technology are connected via communication networks (HART-Multidrop, Profibus, Foundation Fieldbus, etc.) with superordinated units (e.g. control systems, control units). These superordinated units serve for process control, process visualizing, process monitoring as well as for startup, or for servicing the field devices.
Necessary supplemental components for operation of fieldbus systems are components which are directly connected to a fieldbus and which serve, especially, for communication with the superordinated units. Examples of such components include remote I/Os, gateways, linking devices, and controllers. These are frequently also referred to as field devices.
In part, fieldbus systems are also integrated in enterprise networks, which work on an Ethernet basis. In this way, process or field device information can be accessed from different regions of an enterprise.
For worldwide communication, company networks can also be connected with public networks, e.g. the Internet.
Needed for servicing and startup of field devices are corresponding operating programs, e.g. FieldCare, Endress+Hauser; Pactware; AMS, Emerson; Simatic PDM, Siemens).
Serving for plant control and monitoring of larger plants are control system applications, e.g. Simatic S7, Siemens; Freelance, ABB; and Delta V, Emerson).
An essential aspect of open communication systems, such as e.g. Profibus, Foundation Fieldbus or HART, is the interoperability and replaceability of devices of different manufacturers. Thus, sensors or actuators of various manufacturers can be used together without problem. Also, an option is to replace a sensor of a certain manufacturer with a functionally equal sensor of another manufacturer.
Today's field devices are becoming increasingly complex. Besides pure measured value processing, diagnostic tasks and, above all, communication tasks, which field devices must fulfill as regards the installed bus systems, are becoming always more complex. In order to perform these tasks correctly, most often, a plurality of microcontrollers are provided in modern field devices. The advantage in the application of microcontrollers is that, via application-specific, software programs, which run in these microcontrollers, the most varied of functionalities are implementable and program changes can be put into practice relatively simply. Program controlled field devices are therefore very flexible. This high flexibility is, however, gained with the disadvantage that, because of sequential progression through the programs, processing speed is relatively slow.
In part, therefore, in field devices, also so called ASICs (Application Specific Integrated Circuits) are applied. Through their application-specific construction, these chips can process data/signals very rapidly. Especially, they are very suitable for computationally intensive applications.
The functionality of these chips is, however, fixedly predetermined. The use of ASICs is economically feasible only in the case of large piece numbers, since the developmental effort and the therewith connected costs are relatively high. A subsequent changing of functionality is not possible in the case of these chips.
From WO03/098154, a configurable field device is known, wherein a reconfigurable logic chip is provided. Here, during system start, the logic chip, which has at least one microcontroller, which is also referred to as an embedded controller, is configured. After configuration is finished, the required software is loaded into the microcontroller.
The, in such case, required, reconfigurable logic chip must have available sufficient resources, in order to be able to fulfill all desired functionalities. Such “large” logic chips, with much memory capacity, require, however, correspondingly much energy.
The use of smaller logic chips with smaller energy consumption would mean a considerable limitation in the functionality of the field device.